This invention relates to an improved method of recovering benzene from a reforming process, more particularly to improved benzene recovery from a reforming process which provides high benzene yields.
Benzene has enjoyed a continually increasing demand within the marketplace due principally to its versatility as a gasoline blending component and its use in the production of a wide spectrum of petrochemical compounds. Benzene, as well as other aromatic hydrocarbons, are typically produced through a catalytic reforming process in which a naphtha hydrocarbon feed and a hydrogen stream are reacted under pressure and high temperatures in the presence of a catalyst to produce aromatic compounds. Conventional recovery techniques, as shown in FIG. 1, then call for sending the reformer effluent to a flash drum with the bottoms sent to a stabilizer and the majority of vapors recycled back to the reformer feed.
While most of the aromatics including benzene are condensed and recovered as bottoms in the flash drum, a significant amount of benzene may be lost in the vapor stream. This loss of benzene becomes especially pronounced when a reforming process is employed which provides a high benzene yields.
A reforming process which provides high benzene yields will generally utilize a light hydrocarbon feed containing a high percentage of C.sub.6 hydrocarbons (e.g., at least 40% by weight) and which uses a catalyst which under proper reforming conditions produces a stream containing a high benzene concentration. Recovery of benzene from such a stream utilizing conventional recovery techniques becomes increasingly difficult. For example, with a reforming process which produces an effluent containing about 50 wt. % benzene, conventional recovering techniques utilizing a flash drum results in recovering of only about 80 percent by wt. of the benzene in the effluent.
It is a feature of this invention to provide a process for improving the recovery of benzene from a reforming process. It is a further feature of this invention to provide an improved method of recovering benzene from a reforming process which provides high benzene yields.